Drill for mining purposes



Feb. 14, 1933. E. oRMsBY ET AL.

Patented Feb. 14, 1933 UNITED STATES PATENT OFFICE ERLE ORMSBY AND CALVIN P. BASCOM, OF ST. LOUIS, MISSOURI, ASSIGNORS T0 CENTRAL MINE EQUIPMENT COMPANY, OF ST. LOUIS, MISSOURI, A CORPORATION 0F MISSOURI DRILL FOR MINING PURPOSES Application filed December 19, 1928.

This invention relates to drills for mining purposes and also has reference to an improved bit for use in connection with said drills.

An object of the invention is to provide an improved drill for mining purposes, said drill comprising a screw stem and a bit attached to the end of the stem and formed from a plate or blade shaped to provide beveled side cutting edges extending approximately parallel for a distance from their intersection with the end cutting edges and then converging toward the walls of the channels of the stem.

vAnother object of the invention is to provide a bit for use in connection with mining drills composed of a plate or blade notched at its forward end and having forward cutting edges inclining to intersection with approximately parallel lateral cutting edges, all of said cutting edges being beveled and so curved that the outer corners at the lateral cutting edges extend forwardly beyond the planes of other portions of the sides in order to obtain better cutting effect and the forward sides of the bit adjacent the cutting edges being hardened toprovide for automatic sharpening of the bit as an incident to its use.

Another object of the invention is to provide an improved drill for mining purposes including a screw stern having relatively wide peripheral portions so that by Contact with the walls of the hole being drilled the wide surfaces will guide the bit in a straighter line and prevent the formation of the usual deep pits or irregularities, thus obtaining a straighter hole of the desired di ameter.

Another object of the invention is to provide an improved drill for mining purposes comprising a stem characterized as mentioned, in combination with a bit in connection with the end of the stem operating to cut through the mineral in a comparatively straight line under the guidance of the stem.

Other objects will appear from the following description, reference being made t0 the accompanying drawing which illustrates the Serial No. 326,926.

foregoing and other features of the invention and in which Fig. l is a side elevation of a mining drill embodying the present invention.

Fig. 2 is an end elevation looking toward the end of the bit.

Fig. 3 is an enlarged side elevation show- `ijng more clearly improved features of the Fig. 4 is a view looking toward the edge of the bit.

Fig. 5 is a plan view of a plate or blade from which the bit is formed.

Fig. 6 is a plan view of the plate or blade after the same has been stamped or shaped preparatory to being twisted.

b Fig. 7 is a detached view of the complete Fig. 8 is a cross sectional view of the bar from which the advance portion of the drill stem is formed by twisting.

The advance portion of the stem of our improved drill is made of a bar l (Fig. 8) twisted on an axial line to form a screw with spiral channels 2. The peripheral edges 3 of all of the spirals are approximately equidistant radially from the axis of the screw and these peripheral edges are comparatively wide in planes parallel with the axis of the screw so that they present comparatively wide bearing surfaces to engage against the wall of the hole being drilled in the mineral and guide the drill in a straighter line. This prevents the bit from zigzagging or varyingfrom a straight line to such an extent as to vary the hole objectionably from a straight line. Further, by forming the screw stem from a rectangular bar twisted as aforesaid, comparatively sharp corners 4. are provided along the channels 2 and these sharp corners are effective to cut or break protruding points of the mineral that may have escaped the bit.

As shown, the rear or outer end of the guiding portion of the stem above described is kin rigid or integral connection with a spiral elongation 5 of smaller diameter than the advance guidingV portion of the stem. The channels 2 of the advance guiding portion of the stem are in spiral continuation of the channels 6 in the outer portion 5 of the stem. The outer end of the part 5 of the stem is formed with a member 7 for engagement with an operating device or tool.

The advance or forward end of the guiding portion of the stem is formed with a pair of spaced jaws 8 extending longitudinally parallel with the plane of the axis of the drill stem so as to receive between them the end of the bit.

The improved bit shown is made of a plate or blade having an initial form of the plate or blade 9 shown in Fig. 5. Next, a notch 10 is formed in the forward end of this plate or* blade midway between the lateral side edges thereof. A hole 11 is formed intermediate of the ends and intermediate of the side edges of the plate or blade and a notch 12 is made in the rear end of said plate or blade.

The ears 13 formed by the notch 10 are then twisted spirally to provide cutters 14 (Fig. 7 The front edges 15 of the cutters 14 intersect the walls of the notch 10 so as to form sharp cutting corners 16 which are effective to cut through mineral encountered in the operation of the drill. The front edges 15 of the cutters 14 incline to intersection with the lateral edges 17 of said spiral cutters 14. These lateral edges 17 extend approximately parallel with each other and with the ends of the drill to about the points 18 from which the lateral side edges curve to intersection with the walls of the notches 12, as clearly shown.

The front of each cutter 14 is formed with an integral hardened surface 19 while the remaining thickness 2O of the bit is preferably not hardened but is softer and will automatically wear away during operation of the drill more freely than will the hardened edges 19 so that the drill will sharpen itself automatically and as an incident to its operation. l

The width or diameter of the bit in comparison with the diameter of the advance or guiding portion of the stem to which the bit is attached is diagrammatically illustrated in Figs. 1 and 3 wherein it is seen that the lateral cutting edges 17 of the bit will form a hole having walls 21, the diameter of which hole is slightly greater than the diameter of the guiding portion of the drill stem. This permits the drill to operate freely, but due to the novel construction of the guiding portion of the drill stem the bit is guided in a straighter line than would be the case if the bit were attached directly to the end of a drill having the formation of the stem yportion 5, for instance. This drill operates with less effort, with less variation from a straight line and forms a hole of the proper size to a greater 5 depth than other drills with which we are familiar. The drill maintains a sharp cutting edge for a longer time and will last longer than drills of different and ordinary construction now in use. The parallel edges 17 of the bit maintain the hole at proper size throughout all the wearing life of the bit.

The bit formed and constructed in the manner described is attached to the guiding end of the stem by inserting the rear end of the bit between the jaws 8 until the hole 11 is in registration with the hole through said jaws. In this position the bit is fastened to the drillistem by a bolt 22 extending through the jaws 8 and through the hole 11 in the bit while the side walls of the notch 12 engage opposite sides of the guiding portion of the drill stem. Thus, a rigid attachment is obtained so that the drill may be operated with all of the advantages mentioned.

Ve are aware that the construction and arrangement of the device may be varied within equivalent limits without departure from the nature and principle thereof. We contemplate such variations as may be found desirable and do not restrict ourselves in unessential particulars, but what we claim is 1. A bit for a mining drill comprising a plate having a notch in its front end and having sharp corners at the sides of said notch at the end of said plate, and a pair of spiral cutters spaced by said notch and having their front ends inclining laterally to the side edges of said plate and having the forward corners of their front marginal terminal portions in straight parallel planes and having the side edges of said terminal portions inclining inwardly from said corners.

2. A bit for a mining drill comprising a plate having a notch in its front end and having sharp corners at the sides of said notch at the end of said plate, a pair of spiral cutters spaced by said notch and having their front ends inclining laterally to the side edges of said plate and having the forward corners of their front marginal terminal portions in straight parallel planes and having the side edges of said terminal portions inclining inwardly from said corners, and a spiral stem for said bit having its forward portion provided with Wide peripheral bearing edges arranged to engage against the wall of the hole formed by the drill and guide the drill in approximately a straight line and substantially prevent the drill from oscillating, the rear portion of said spiral stem being of less diameter than said forward portion and axially alined therewith.

8. A bit for a mining drill comprising a plate of approximately uniform thickness throughout and having a notch in its forward end and having sharp angles at the sides of said notch at the forward end of said plate, and a par of spiral cutters spaced by said notch and having their front ends inclining to the side edges of the plate and their f'ront marginal portions in approximately straight parallel planes and nclining inwardly from the front corners of said cutters, the integral front surface of said cutters at each side of said notch being hardened.

ERLE ORMSBY. CALVIN P. BASCOM. 

